Yeah, it is playtime, along with a power-up collect percentage. The font is the same I use for the rest of the in-game texts, but I get what you're saying.
Just on this screen alone, I'm using three different "fonts" (life numbers are drawn with images so it isn't really a font but whatever). I could perfectly replace it with one of the others, either LCD-like numbers (it would match with the LCD screen aesthetic), or the text font (I believe it was Impact). I feel more inclined to the first.
Thanks ;).